SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '102be52323ddbc7ab9ac793a471e03f0ff4425793e24b0da5fbf421e3febb7bc' 
  AND token = 'P6BH/9XsP0YUkY4LvqEnTKFdfZnxSrGPJ24dyJ9owiY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}